Slated for November 6, the midterm elections, which take place every four years, will for the next two years shape President Donald Trump's chances to push his agenda on tightening immigration, dismantling the Obama-era Affordable Care Act (ACA) and other key campaign promises.

Coming on the heels of two years of increased polarisation in the country, the midterms will determine all 435 seats in the House of Representatives and 35 of the 100 seats in the Senate. The vote will also decide 39 state and territorial governorships.

As Democrats hope to mobilise voters, the elections are expected to be a referendum on Trump's controversial policy programmes.

{articleGUID}

Although the statistics website FiveThirtyEight predicts that Democrats have a one-in-six chance of gaining a majority in the Senate, it puts the party's hopes of taking the House of Representatives at nearly 88 percent.

Several key House races across the country will put those expectations to the test.

Here are some of the key races you should keep an eye on during the November 6 elections:

Kentucky's 6th District

During the November 2016 presidential vote, Donald Trump won Kentucky by a landslide, pulling in an overall 62.5 percent of the vote. But while the state is overwhelmingly Republican, a heated race is shaping up in Kentucky's 6th district.

The district is situated in central Kentucky and includes Lexington, Richmond and Frankfort, the state capital. Andy Barr, a lawyer and Republican incumbent who has been in power since 2013, is fighting off an increasingly popular Democratic challenger, Amy McGrath, a former Marine fighter pilot.

Polls have repeatedly put the race neck-and-neck: According to a Sienna College and New York Times survey, Barr and McGrath were both polling at 44 percent just days before the vote.

FiveThirtyEight considers this race a toss-up, with Barr having a five-in-nine chance of winning.

California's 48th District

Based in Orange County, a traditionally conservative stronghold in southern California, the state's 48th district race may be one of the few votes where the ongoing Russia investigation may help determine the outcome.

At a time of increasing consternation over allegations of Russian meddling during the 2016 presidential vote, Dana Rohrabacher, the longtime Republican incumbent, has faced criticism over his favourable view of Russia and its president, Vladimir Putin.

Democratic challenger Harley Rouda, a businessman and former Republican, is hoping to ride this wave to replace Rohrabacher. A Sienna College and New York Times poll put Rouda at 46 percent and Rohrabacher at 45 percent.

{articleGUID}

Rouda has also campaigned on issues of income equality - in a district with a massive wealth gap. For his part, Rohrabacher has doubled down in his support for Trump and made no secret of his support for Russia.

FiveThirtyEight has this race leaning Democrat, with Rouda having a 56 percent chance of winning.

Texas's 32nd District

In the 32nd district of Texas, a state known for its widespread Republican support, Democratic challenger Colin Allred is facing off against Republican incumbent Pete Sessions, who did not face a Democratic opponent in 2016.

Encompassing wealthy suburbs in northeastern Dallas, the area is home to more than 750,000 people and went to Democratic presidential candidate Hillary Clinton two years ago.

A 35-year-old civil rights lawyer and former NFL player, Allred has focused his campaign on expanding healthcare access, immigration reform and measures to prevent gun violence.

Sessions, a Trump-backed conservative who assumed office in 2003, has in the past enjoyed the Dallas Morning News's endorsement. Polls have gone back and forth, but the most recent Sienne College survey put Allred at 46 percent and Sessions at 42 percent.

Analysts say an Allred victory would be a large blow to Republicans in a district that has sent Sessions to Washington, DC, several times.

FiveThirtyEight predicts Sessions has a 63 percent chance of winning this race.

New York's 19th District

A swing district in New York's Hudson Valley, the state's 19th district is currently home to a heated race between Republican incumbent John Faso and Democratic nominee Antonio Delgado, a 41-year-old African American lawyer.

After former President Barack Obama won the district twice, Trump won in November 2016.

Healthcare has dominated the local debate in the lead-up to the midterm vote, and FiveThirtyEight estimates that Democrats have a three-in-five chance of taking back the district.

Faso, a lawyer, has pushed back against Delgado, accusing him of supporting a single-payer healthcare system. Faso's campaign has also criticised Delgado's past as a rapper, prompting accusations of racism.

{articleGUID}

But Delgado's campaign has attempted to focus the election discourse around Faso's support for Republican efforts to dismantle Obama-era healthcare legislation.

Another heated debate in New York's 19th district has been immigration.

A recent Survey USA poll put both candidates at 44 percent.

Illinois's 14th District

A district that includes Chicago's suburbs, Illinois's 14th went to Trump by four percentage points two years ago. Four years before that, the district went to Mitt Romney, the Republican candidate who lost to Obama in 2012.

Republican incumbent Randy Hultgren, who has held his seat since 2011, raised $1.4m between January and September, compared with Democratic challenger Lauren Underwood's $1.1m since April 2017.

Hultgren has been a mixed bag on Trump, praising the president's economic programme and the low unemployment rate while decrying his tone and efforts to "significantly" decrease the number of refugees entering the US. Amid Trump's crackdown on refugees, Hultgren has called for a simpler process for people fleeing war and other dangers.

But Underwood, a 33-year-old African American teacher, has placed reducing gun violence, protecting the environment and improving education high on her campaign platform.

FiveThirtyEight predicts that Underwood has a 70-percent likelihood of replacing Hultgren.

Iowa's 1st District

In the northeastern part of Iowa sits the state's first congressional district, where a trade war could cost Republican incumbent Rod Blum his seat.

Blum was elected in 2014 and is seen as a byproduct of the Tea Party, the right-wing movement within the Republican Party. Although the district went to former President Obama twice, Trump won by four points in 2016.

Blum, who has landed in hot water over alleged House ethics violations, is squaring off against Democratic challenger Abby Finkenauer.

Finkenauer, 29, was elected to the Iowa state legislature in 2014 and has placed a focus on advocating pro-labour policies and reproductive rights. She currently leads the polls, with FiveThirtyEight giving her a 95-percent chance of flipping the district to Democratic control.

If Finkenauer wins, she could join New York progressive Alexandria Ocasio-Cortez as the first women under 30 to be elected to Congress.

California's 39th District

Stretching across parts of Los Angeles, Orange and San Bernardino counties, California's 39th district is home to a diverse population.

A hotly contested battle is brewing in the swing district, where Republican Ed Royce was reelected in 2014 despite the presidential vote going to Hillary Clinton in 2016.

With Royce retiring at the end of the term, Democrats hope to flip the district, which FiveThirtyEight considers likely.

The most recent Sienna College-New York Times poll predicts 48 percent support for Cisneros as compared to 47 percent for Kim. Despite the close polling, FiveThirtyEight gives the Democrat a four-in-seven chance of winning.

{articleGUID}

Cisneros, a multimillionaire Democrat, has outspent Kim by a five-to-one margin. Kim, a former staffer for Royce, has not garnered Trump's endorsement. In the past, she has taken positions that defy Trump's policies.

Cisneros has fielded sexual harassment allegations that were later withdrawn, but it remains unclear whether the accusations have harmed his campaign. Seizing those allegations, the Congressional Leadership Fund, a Republican PAC, ran a series of ads describing Cisneros as "disgusting" and "shady".